Observations on the Human Voice

399

ing. I have little doubt but the Varna and Balaklava wire will be
the best yet made for the purpose.

Without knowing exactly what the " retardation " may be in
terms of the element of time *' a " of the diagrams, we may judge
what the retardation, if similarly estimated, would be found to be in
other cables of stated dimensions. Thus, if the retardation in 200
miles of submarine wire between Greenwich and Brussels be ^^th of
a second, the retardation in a cable of equal and similar transverse
section, extending half round the world (14,000 miles), would be

( . _) s/ — =490 seconds, or 84- minutes ;

V 200 J 10 ^

and in the telegraphic cable (400 miles) between Varna and
Balaklava, of which the electro-statical capacity per unit of length
may be about one -half greater than in the other, while the conduct-
ing power of the wire is probably the same, the retardation may be

expected to be

/400\2^S 13. ,

/ — X—X — =— or a second.

\200y 2 10 5

The rate at which distinct signals could be propagated to the
remote end would perhaps be one signal in about a quarter of an hour
in the former case, and nearly two signals in a second in the latter.

IV. ^^ Observations on the Human Voice.^^ By Manuel Garcia^
Esq. Communicated by Dr. Sharpey^ Sec. E.S. Re-
ceived March 22, 1855.

The pages which follow are intended to describe some observa-
tions made on the interior of the larynx during the act of singing.
The method which I have adopted is very simple. It consists in
placing a little mirror, fixed on a long handle suitably bent, in the
throat of the person experimented on against the soft palate and
uvula. The party ought to turn himself towards the sun, so that
the luminous rays falling on the little mirror, may be reflected on
the larynx. If the observer experiment on himself, he ought, by
means of a second mirror, to receive the rays of the sun, and direct
them on the mirror, which is placed against the uvula. We shall

400

now add our own deductions from the observations which the image
reflected by the mirror has afforded us.

Opening of the Glottis.

At the moment when the person draws a deep breath, the epi-
glottis being raised, we are able to see the following series of move-
ments : — the arytenoid cartilages become separated by a very free
lateral movement ; the superior ligaments are placed against the ven-
tricles ; the inferior ligaments are also drawn back, though in a less
degree, into the same cavities ; and the glottis, large and wide open,
is exhibited so as to show in part the rings of the trachea. But
unfortunately, however dexterous we may be in disposing these
organs, and even when we are most successful, at least the third
part of the anterior of the glottis remains concealed by the epi-
glottis.

Movement of the Glottis.

As soon as we prepare to produce a sound, the arytenoid carti-
lages approach each other, and press together by their interior
surfaces, and by the anterior apophyses, without leaving any space,
or inter cartilaginous glottis ; sometimes even they come in contact
so closely as to cross each other by the tubercles of Santorini. To
this movement of the anterior apophyses, that of the ligaments of
the glottis corresponds, which detach themselves from the ventricles,
come in contact with different degrees of energy, and show them-
selves at the bottom of the larynx under the form of an ellipse of a
yellowish colour. The superior ligaments, together with the ary-
teno-epiglottidean folds, assist to form the tube which surmounts
the glottis ; and being the lower and free extremity of that tube,
enframe the ellipse, the surface of which they enlarge or diminish
according as they enter more or less into the ventricles. These last
scarcely retain a trace of their opening. By anticipation, we might
say of these cavities, that, as will afterwards appear clearly enough
in these pages, they only afford to the two pair of ligaments a
space in which they may easily range themselves. When the
aryteno-epiglottidean folds contract, they lower the epiglottis, and
make the superior orifice of the larynx considerably narrower.

The meeting of the lips of the glottis, naturally proceeding from
the front towards the back, if this movement is well managed, it

401

will allow, between the apophyses, of the formation of a triangular
space, or inter- cartilaginous glottis, but one which, however, is
closed as soon as the sounds are produced.

After some essays, we perceive that this internal disposition of
the larynx is only visible when the epiglottis remains raised. But
neither all the registers of the voice, nor all the degrees of intensity,
are equally fitted for its taking this position. We soon discover
that the brilliant and powerful sounds of the chest-register contract
the cavity of the larynx, and close still more its orifice ; and, on the
contrary, that veiled notes, and notes of moderate power, open both
so as to render any observation easy. The falsetto register especial-
ly possesses this prerogative, as well as the first notes of the head-
voice^. So as to render these facts more precise, we will study in
the voice of the tenor the ascending progression of the chest-
register, and in the soprano that of the falsetto and head-registers.

Emission of the Chest-voice,
If we emit veiled and feeble sounds, the larynx opens at the notes

do, re, mi, -gp=r=zrzzrziz=r=:^.
2 2 2 ^====- I '

and we see the glottis agitated by large and loose vibrations through-
out its entire extent. Its lips comprehend in their length the ante-
rior apophyses of the arytenoid cartilages and the vocal cords ; but,
I repeat it, there remains no triangular space.

As the sounds ascend, the apophyses, which are slightly rounded
on their internal side, by a gradual apposition commencing at the
back, encroach on the length of the glottis; and as soon as we

* Let us here observe, that three registers of voice are generally admitted, —
chest, falsetto, and head. The first begins lower in a man's voice than in a
woman's ; the second extends equally in both voices ; the third reaches higher in
the female voice.

Table of the Human Voice in its full extent.

/ Chest N. X

.__^— „ ±- -t- -h-

^^« / p ,-, ', ■

*'' i /l # > » -

neau

/ ( "S 4J«'-'-

/ k.u / " —

_o- *^ _^. Falsetto J

t The musical limits we establish in the course of these pages vary a little in
each individual.

402

reach the sounds si, do, |fc^=ii^=, they finish by touching each

3 3 '^EEEEE^

other throughout their whole extent; but their summits are only

solidly fixed one against the other at the notes do J, re, dMt|:s:z=orz .

3 3 ^—

In some organs these summits are a little vacillating when they
form the posterior end of the glottis, and the two or three half-tones
which are formed show a certain want of purity and strength, which

is very well known to singers. From the do;f , re, zH— gi^zizoz^ the

3' 3 $EEEr=r£iz

vibrations, having become rounder and purer, are accomplished by
the vocal ligaments alone, up to the end of the register.

The glottis at this moment presents the aspect of a line slightly
swelled towards its middle, the length of which diminishes still
more as the voice ascends. We also see that the cavity of the larynx
has become very small, and that the superior ligaments have con-
tracted the extent of the ellipse to less than one-half.

When instead of veiled and feeble sounds, we make use of full
and vibrating ones, the glottis becomes visible only at the sounds

mi, fa, flEi~z=^E» ^^^ those above them, a limit which depends
3 3

to a certain extent on the dexterity of the singer. For all the rest,
the organs act as we have just said, but with a double difference :
1. The cavity of the larynx contracts itself more when the voice is
intense, than when it is feeble, 2. The superior ligaments are con-
tracted so as to reduce the small diameter of the ellipse to a width
of two or three lines. But however powerful these contractions
may be, neither the cartilages of Wrisberg, nor the superior liga-
ments themselves, ever close sufficiently to prevent the passage of
the air, or even to render it difficult. This fact, which is verified
also with regard to the falsetto and head-registers, suffices to prove
that the superior ligaments do not fill a generative part in the forma-
tion of the voice. We may draw the same conclusion by consider-
ing the position occupied by the somewhat feeble muscles which
correspond to these ligaments ; they cover externally the extremity
of the diverging fibres of the thy ro- arytenoid muscles, and take
part especially in the contractions of the cavity of the larynx during
the formation of the high notes of the chest- and of the head-
registers.

408

Production of the Falsetto,

The low notes of the falsetto, fezzzzizzizzzizzzzzi: sol, la|^, latj,

^ ~ te^ §^^ 2 2 2

show the glottis infinitely better than the unisons of the chest-voice

and produce vibrations more extended and more distinct. Its

vibrating sides, formed by the anterior apophyses of the arytenoid

cartilages, and by the ligaments, become gradually shorter as the

voice ascends ; at the notes la, si, ^^i^EE^EE' ^^ apophyses take

3 3 J— -—

part only at their summits ; and in these notes there results a weak-
ness similar to that which we have remarked in the chest-notes an
octave below. At the notes dojf, re, 2,E|iEjEi^zE:, the ligaments

alone continue to act ; then begins the series of notes called head-
voice. The moment in which the action of the apophyses ceases,
exhibits in the female voice a very sensible difference at once to the
ear and in the organ itself. Lastly, we verify, that, up to the highest
sounds of the register, the glottis continues to diminish in length
and in width.

If we compare the two registers in these movements, we shall find
some analogies in them : the sides of the glottis, formed at first by
the apophyses and the ligaments, become shorter by degrees, and
end by consisting only of the ligaments. The chest-register is
divided into two parts, corresponding to these two states of the
glottis. The register of falsetto-head presents a complete similarity,
and in a still more striking manner.

On other points, on the contrary, these same registers are very
unlike. The length of the glottis necessary to form a falsetto note,
always exceeds that which produces the unison of the chest. The
movements which agitate the sides of the glottis are also aug-
mented, and keep the vibrating orifice continually half opened, which
naturally produces a great waste of air. A last trait of difference,
is in the increased extent of that elliptic surface.

All these circumstances, which we shall refer to again, show in
the mechanism of the falsetto, a state of relaxation, which we do not
find in the same degree in the chest-register.

Manner in which the sounds are formed.

As we have just §aid, and what we have seen proves it, the in-^
¥0L. \ii. 2 Q

404

ferior ligaments, at the bottom of the larynx, form exclusively the
voice, whatever may be its register or its intensity ; for they alone
vibrate at the bottom of the larynx*. But by virtue of what prin-
ciple is the voice formed ? It seems to me, that the answer to this
question can be but this ; the voice is formed in one unique manner,—
hy the compressions and expansions of the air, or the successive and
regular explosions which it produces in passing through the glottis.

The ligaments of the glottis are situate about the mean level of
the upper border of the cricoid, close the passage, and present a
resistance to the air. As soon as the air has accumulated suffi-
ciently, it parts these folds and produces an explosion. But at the
same instant, by virtue of their elasticity, and the pressure from be-
low being relieved, they meet again to give rise to a fresh explosion,
A series of these compressions and expansions, or of explosions,
occasioned by the expansive force of the air and the reaction of the
glottis, produces the voice.

This theory, though now generally admitted for reeds, and un»
doubtedly evident in the liquid vein, the toothed-wheel of Savart,
the syrene of the Baron Cagnard Latour &c., has not to my know-
ledge, been yet applied to the glottis f. If we consider that the
lips of this aperture, taken separately, can give no kind of sounds
however we may try to make them speak, we must admit that the
sounds which they give forth by their mutual action, are only owing
to the explosions of the air produced by their strokes J. It is not
necessary in order to obtain the explosion of sound, that the glottis
should be perfectly closed each time after its opening ; it suffices
that it should oppose an obstacle to the air capable of developing its
elasticity. In this case the rushing of the air is heard accompanying

* We gladly acknowledge that this most important fact has been already
announced by J. Miiller, although we have our objections to the theory which
accompanies it. — Handbuch der Physiologie des Menschen.

t I find that Dr. Miiller hints at the possibility of the voice being thus formed,
but only to attack and reject the notion. — Ibidem,

X Many controversies have arisen respecting the sounds sometimes emitted by
animals after the section of the superior and recurrent laryngeal nerves ; sounds
which have been perhaps occasioned by the struggling of the animal causing a
swelling of the neck and a mechanical contact of the vocal ligaments. However,
without doubt, after the section of these nerves, voice, as a voluntary act, can no
longer take place. ■

405

the sounds, and they take a veiled, and sometimes an extremely
muffled character ; an observation which we have already presented
to the reader's notice in speaking of the falsetto.

Conjectures on the Formation of the different Registers,

As the entire system of vibrations arises solely from the inferior
ligaments, it is evident that the cause of the different tones called
registers, must be sought for in the muscles which set these liga-
ments in motion ; and that the other parts of the larynx must be
considered only as apparatus for strengthening the sounds obtained,
and for modifying their quality. In our efforts to discover the more
intimate processes of the vocal organs which produce the sounds,
we shall recur at once to the observations already mentioned, to
some anatomical remarks which we are going to make, and to the
sensations which we feel in the organ itself whilst it is producing
sounds.

If we detach one of the halves of the thyroid cartilage, we shall
see a large muscular surface of oblique fibres, which fills all the
space between the arytenoid and thyroid cartilages. At its upper
end is to be seen the muscle corresponding to the superior vocal
ligaments, and which sometimes extends to the notch in the
thyroid. After detaching this generally frail muscle, all the fibres
constituting this muscular surface seem to start from two opposite
centres, viz. the anterior surface of the arytenoid, and the re-enter-
ing angle of the thyroid. These centres, occupying the extremities
of a diagonal line, send their fibres towards each other in parallel
lines. Those which start from the anterior face of the arytenoid
descend obliquely ; the most external ones go to the cricoid, whose
posterior half they cover at the side ; the most internal ones de-
scend to the vocal membrane*, which they cover entirely. The
fibres which terminate at the membrane become longer, as they be-
come more internal. Those which start from the re-entering angle
of the thyroid, reascend obliquely to the summit of the arytenoid,
then diverge in order to form the sides of the ventricles, and then
disappear in the aryteno-epiglottidean folds and even the under sur-
face of the epiglottis. If we cut it away in successive layers, pro-

* We thus designate that part of the membrane which goes from the bottom
of the vocal ligament, to the edge of the cricoid.

2 q2

406

ceeding/rom the outside to the in, we reach a thick bundle of fibres,
perfectly horizontal, which line the outer aspect of the vocal liga-
ment, and which go from the anterior apophyses of the arytenoid
to the re-entering angle of the thyroid*.

This bundle has its posterior half covered by the lateral crico-
arytenoid muscle, and its anterior half by the diverging fibres which
start from the thyroid. If we cut away the horizontal bundle in
successive layers, we see that the fibres are not all of the same
length ; the most external fibres are the longest, and the succeeding
ones get gradually shorter as they become more internal ; but they
all originate in the anterior cavity of the arytenoid, and the muscle
is inserted in the manner above explained throughout the whole
length of the vocal ligaments, the thyro- arytenoid portion of it ex-
cepted. As the fibres all begin from the arytenoid, and terminate
successively at more distant points of the membrane, we see that the
muscle is thicker behind than before.

Thus the vocal ligament, and the membrane which depends from
it, the sole sources of all vocal sounds, are under the direct action of
the fibres which come from the anterior cavity of the arytenoid ; the
ligament under the action of the horizontal bundle, the membrane
under that of the oblique fibres. The long horizontal fibres, ex-
tending from one cartilage to the other, are placed at the exterior of
the short horizontal fibres, and at the interior of the oblique fibres.
The diverging fibres which start from the thyroid, acting only on
the superior vocal ligaments and the folds, seem to influence by
their contractions only the quality and volume of the voice.

The remarkable arrangement of the fibres which we have just ex-
amined, enables us to explain a fundamental fact,— the elevation of
the voice. The fibres of the horizontal bundle being placed over
each other, in layers, one covering the other, and getting gradually
longer and longer, as they become more external, extend their action
to the more anterior parts of the edges of the glottis. This progress-
ive action from the back to the front, encroaches gradually on the
length of the vibrating portion of the ligament, and likewise increases
its tension, and its faculty of accelerating its pulsations*

Another portion of the thyro -arytenoid muscle at the same time
stretches and raises the vocal membrane more and more, causing a
^ Another portion of the thyro»arytenoid muscle.

407

lesser depth of the ligaments to be in contact, in proportion as the
sounds become higher, and thus assists by increasing the mobility
of the ligaments.

We shall see in a few moments that the rotatory movement,
which the external fibres of the lateral crico-arytenoid muscles give
to the arytenoid, by making the vocal membrane deeper, partly
counteracts the above effect, and produces the chest-register.

The crico-thyroid muscle, on the contrary, is a powerful auxiliary
in the elevation of the voice. This muscle, which at the same time
causes the thyroid to come forwards and downwards, gives rise to a
mechanical tension, not only in the vocal ligament, but even in the
whole vocal membrane. The meeting of the thyroid and cricoid
cartilages, which we can feel by the touch, becomes especially
marked when the inter- ligamentous glottis alone produces the sounds.

-€>-

which takes place as we have seen at the notes dof , re? §5^^^

in the chest-register, and an octave above for that of the head ; with
this difference, however, that for the latter a more vigorous and
complete connexion is necessary.

Let us now see what we may learn from the sensations we feel in
the vocal organ. When we produce a chest-note, the least attention
enables us to distinguish a ''pinching " at the posterior part of the
glottis, which becomes more vigorous as the notes ascend. This
pinching seems to be formed by extension of the depth of the touch-
ing surfaces, and may become very painful ; whilst the notes of fal-
setto, when higher than chest ones, give comparatively great relief to
this part, and the surfaces in contact seem to have become thinner.

If we combine these sensations with the different remarks which
have been furnished to us by the examination of the muscles, we
can fix the particular mechanism of each register.

Chest Register.

In fact, when the arytenoid muscles have brought in contact the
arytenoid cartilages, and closed the glottis, the voice may take two
very different characters ; nay, more, it will be produced in pitches
widely apart from one another, and will give forth the chest, or
falsetto registers, according as the fibres of the thyro-arytenoid
attached to the vocal membrane are active or not. By the action

408

of these fibres, as we have seen, this muscle raises the vocal mem-
brane, and makes its apposable part thinner; whereas the lateral
crico-arytenoid gives a rotatory movement to the cartilage, which
brings the apophyses into deep contact. This deep contact, which
continues even after the apophyses no longer partake in the vibra-
tions, gives a deep tension to the membranes, increases the depth of
their contact*, and, as a necessary consequence, augments the re-
sistance they present to the air. It is to the extent of this resistance
that we attribute the formation of the chest-registerj so distinct by
its particular amplitude. To it we attribute also the slowness of
the beats of the glottis, and the consequent low pitch of the sounds,
a pitch which, even in the highest tenor voices, is at least an octave
lower than the head notes of ordinary soprani.

Register of Falsetto,

When, on the contrary, the external fibres of the lateral crico-
arytenoid muscle i^emain inactive, we produce the falsetto. The
lips of the glottis, stretched by the horizontal bundle of the thyro-
arytenoid, come in contact by their edge alone, formed at once by
the ligament and the apophyses, and offer little resistance to the
air. Hence arises the great loss of this agent, and the general
weakness of the sounds produced here.

But as soon as we reach the sound do, the beats are produced by

the ligaments exclusively, and we have attained the head-register.
It is certain, as we may deduce from the movement of the ligaments,
that then the vocal membrane is raised by the action of the fibres of
the thyro-arytenoid muscle, and its surface is diminished to an edge ;
but we think that the external fibres of the lateral crico-arytenoid,
which would prevent this movement, remain inactive. Then also
the very decided tension, which the crico- thyroid muscle effects on
the vocal tendons, and which accelerates their movements^ takes
place.

During the chest-register, therefore, the vocal ligaments are
stretched, and are in contact to an extent corresponding with the
depth of the anterior apophyses of the arytenoid, whilst in the
falsetto the edges alone of the ligaments are stretched and apposed ;
in both cases the sounds being formed, not by the actual vibrations

* It is then that we feel the pinching of which we have spoken.

409

of either the whole or part of the tendons, but by the successive
explosions which they allow.

Pressure of the Air,

Until now, in our remarks on the manner in which the voice is
formed, we have only referred to the rigidity of the glottis, a rigidity
necessary to accomplish the 1056 vibrations in one second'*, which
form the do of the chest-voice, and to accomplish the double number

4

which produces the octave above in the head- voice. There is, notwith-
standing, another indispensable element for the production of vocal
sounds, the pressure of the air. Pressure, as is well known, developes
an elastic force in this agent, in a degree inverse to the volume
which it occupies. It is by means of this power that the intensity
of the sounds is obtained. The intensity of the sound can only de-
pend on the quantity of air which goes to each sharp explosion. I
say sharp explosion, as an express condition : the glottis should
close itself perfectly after every vibration ; for if the air found a con-
stant passage, as in the notes of falsetto, then the greatest move-
ments of the glottis, and the greatest waste of air, would produce
precisely the weakest notes. To reject this theory would be to
attribute the intensity of the sound to the extent of the vibrations
accomplished by the lips of the glottis, and to suppose that these
lips, each taken separately, possess the power of producing sounds,
suppositions quite contrary to the facts.

The elastic force of the air arises not only from the compression
of the lungs, but also from the contractions of the trachea, which
adjusts its calibre to the different dimensions of the glottis. It is
by means of this force that the air conquers the continually-in-
creasing obstacle presented by the lips of the glottis when they
produce sounds more and more intense.

Thus the problem of the elevation of the voice, always complicated
with that of its intensity, in order to be complete, ought to show
the connexion which exists between the tension of the lips of the
glottis, the pressure of the air, and the number and intensity of the
explosions obtained. As a consequence, we may state that the
greater pressure of air necessary to produce the greater intensity,

* Pouillet, Physique f Sixth Edition, vol. ii. page 11.

410

would at the same time increase the number of pulsations, and so
raise the tone ; but to prevent this, the glottis must at the same
time be lengthened, and vice versa ; or, in other words, that the dif-
ferent lengths of the glottis can, under different degrees of pressure,
produce the same number of shocks, but at different degrees of
intensity.

Of the Qualities of the Voice.

Various simultaneous causes modify the qualities of the voice :—
1, according as the glottis partially or entirely closes the passage
between the explosions, it produces veiled or brilliant sounds ; 2, the
tube which surmounts and surrounds it also greatly affects the
quality of the voice ; by its contractions it gives brilliancy to it and
its widening volume ; 3, the epiglottis also plays a very important
part^ for every time that it lowers itself, and nearly closes the orifice
of the larynx, the voice gains in brilliancy ; and when, on the other
hand, it is drawn up, the voice immediately becomes veiled.